Well casing hanger with releasable slip means



March 12, 1963 J. A. HAEBER 3,081,113

WELL CASING HANGER WITH RELEASABLE SLIP MEANS Filed Aug. 10, 1960 5Sheets-Sheet 1 INVENTOR:

J.A. HAEBER HIS AGENT March 12, 1963 J. A. HAEBER 3,081,113

WELL CASING HANGER WITH RELEASABLE SLIP MEANS Filed Aug. 10, 1960 sSheets-Sheet 2 j T, N

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HIS AGENT March 12, 1963 J. A. HAEBER 3,081,113

WELL CASING HANGER WITH RELEASABLE sup MEANS Filed Aug. 10, 1960 5Sheets-Sheet 3 90 I: 92 m [a FIG. 3

FIG v4 INVENTOR:

J.A. HAEBER HlS AGENT March 12, 1963 J. A. HAEBER WELL CASING HANGERWITH RELEASABLE SLIP MEANS 5 Sheets-Sheet 4 Filed Aug. 10, 1960INVENTOR:

J.A.HAEBER BY: Hu CwvEi HIS AGENT March 12, 1963 J. A. HAEBER WELLCASING HANGER WITH RELEASABLE SLIP MEANS 5 Sheets-Sheet 5 Filed Aug. 10,1960 J.A. HAEBER HIS AGENT INVENTORZ BY: Hfb C United States Patent 3081 113 WELL CASING HADlGElR WITH RELEASABLE SLIP MEANS John A. Haeber,Houston, Tex., assignor to Shell Oil Company, New York, N.Y., acorporation of Delaware Filed Aug. 10, 1960, Ser. No. 48,646 4 Claims.(Cl. 28523) This invention relates to apparatus for use at offshore wellinstallations and pertains more particularly to a well casing hangeradapted to anchor a string of well casing in an underwater wellcasinghead, and it further pertains to equipment for lowering andsetting a casing hanger or other wellhead equipment within an underwaterwell casinghead and/or subsequently retrieving various pieces ofequipment from the well casinghead.

In an attempt to locate new oil fields an increasing amount of welldrilling has been conducted at offshore locations, such for example, asolf the coasts of Louisiana, Texas and California. As a general rule,the strings of casing in a well, together with the tubing string orstrings, extend to a point well above the surface of the water wherethey are closed in the conventional manner that is used on land wells,with a conventional wellhead assembly being attached to the top of thecasing. Attempts have been made recently to provide methods andapparatus for drilling, completing and working-over a well wherein boththe well casinghead and the various wellhead components secured theretoor suspended therefrom are located underwater at a depth suflicient toallow ships to pass over them. Preferably, the casinghead and itsassociated equipment is located close to the ocean floor. In order toinstall equipment of this type underwater in depths greater than theshallow depth at which a diver can easily operate, it has been necessaryto design entirely new equipment for this purpose. Thus, after drillingand completing an oil or gas well at an offshore location in a mannerdescribed in copending patent application, Serial No. 830,538, filedJuly 30, 1959, and en titled Underwater Well Completion Method, stringsof casing may be run into the well and suspended from the wellcasinghead by equipment of the present invention.

It is a primary object of the present invention to provide a casinghanger adapted to be secured to the top of a string of well casing andanchored within a well casinghead for fixedly positioning the wellcasing in the well against well pressures or thermal expansion tendingto raise the casing hanger off its seat within the well casinghead.

Another object of the present invention is to provide well casing hangerapparatus provided with anchoring means normally held in a retractedposition while the well casing and hanger is being run into the well andseated in the well casinghead, and adapted to be remotely actuated toset the anchoring means against the casinghead.

A further object of the present invention is to provide a well casinghanger with anchoring means adapted to be locked in a cocked,inoperative position while being transported to a drilling location.

These and other objects of this invention will be understood from thefollowing description taken with reference to the drawing, wherein:

FIGURE 1 is a diagrammatic view illustrating a floating drilling bargeanchored to the ocen floor over a drilling location while a string ofwell casing is being installed in the well;

FIGURES 2 and 2A are side by side views taken in longitudinalcross-section of a casing hanger of the present invention seated withina casinghead with a running tool or connector device being shown aspositioned within the casing hanger while being secured to a pipestring;

3,081,113 Patented Mar. 12, 1963 FIGURES 3 and 4 are views taken inenlarged detail and in longitudinal cross-section of two types of valvesarranged to be employed with the running tool connector of FIGURE 2;

FIGURE 5 is a front view of a portion of the slip assembly employed onthe casing hanger assembly of FIGURE 2;

FIGURE 6 is a cross-sectional view taken along the line 6-6 of FIGURE 5;

FIGURE 7 is an enlarged detail view of a latching pin of the casinghanger of FIGURE 2; and,

FIGURE 8 is a View taken in longitudinal section of a cross-over dart.

Referring to FIGURE 1 of the drawing, a drilling barge 11 of anysuitable fixed or fioatable type is illustrated as floating on thesurface of the water 12 and substantially fixedly positioned over apreselected drilling location by being anchored to the ocean floor 13 byanchor lines 14 and 15 running to anchors (not shown) sunk in the oceanfloor. Equipment of this type may be used when carrying on welldrilling, Well completion, or well maintenance operations in watervarying from about to 1500 feet or more. The drilling barge is equippedwith a suitable derrick 16 containing fall lines 17 and a hoist 18, aswell as other auxiliary equipment needed during the drilling orservicing of a well. Thus, in this instance the drilling rig is shown asbeing provided with a traveling block 21 to which is secured a pair ofelevators 22 or other suitable means for connecting to the top of astring of pipe 23. A flexible hose 24 is provided and is adapted to besecured to the top of the pipe string 23 at any time it is desired toprovide a source of hydraulic fluid through the pipe string '23. Theflexible hose 24 is in communication with a pump 25 or any othersuitable source of hydraulic pressure fluid.

The derrick 16 is positioned over a drilling slot or well 26 whichextends vertically through the barge 11 in a conventional manner. Whenusing the equipment of the present invention, the slot 26 in the barge11 may be either centrally located or extend in from one edge. Howeveroperations with the apparatus of the present invention may be carriedout over the side of the barge without use of the slot.

A wellhead support structure, which is represented by a horizontallyextending support frame 27 having a casinghead secured thereto andcentrally positioned thereon, is illustrated as being anchored to theocean floor by means of a conductor pipe or surface casing 31 which isthen installed in and preferably cemented in the ocean floor 13. Securedto the wellhead support frame 27 are two or more guide columns 32 and 33having guide cables 34 and 35 extending vertically therefrom to thedrilling barge 11 where they are preferably secured to the barge bymeans of constant tension winches 36 and 37. The guide cables 34 and 35are provided for the purpose of guiding pieces of equipment from thebarge 11 into alignment on or in the casinghead 28 positioned on theocean floor. In FIGURE 1, a string of well casing 40 is shown as beinglowered into the casinghead 28 by means of a pipe string 23 whichextends to the barge 11 and is suspended by means of the elevators 22.The well casing 40 has a casing hanger 41 fixedly secured to the topthereof whereby the casing may be hung from the casinghead 28. Duringthe lowering operation, the casing hanger 41 is secured to a connectordevice 42 in a releasable manner, the connector device 42 in turn beingfixedly secured to the lower end of the pipe string '23.

Referring to FIGURE 2, the casing hanger body member 41 is shown asbeing provided with a downwardly and inwardly sloping seating surface orshoulder 39 which is adapted to cooperate with a mating sloping shoulder43 formed on the inner wall of the casinghead 28 or any other suitablecasing and tubing suspension housing. One or more O-ring seals or othersuitable packing is preferably carried outwardly on the seating shoulder39 of the casing hanger for forming a fluidtight seal between shoulders39 and 43. Another seating shoulder 45 may be provided on the inner wallof the casing hanger body member 41 for seating the lower end of theconnector device 42 within the bore 46 of the casing hanger 41, or forseating subsequent concentric casing hangers (not shown) therein.

Formed is preferably a recessed manner on the outer surface of thecasing hanger body member 41 is a downwardly and outwardly sloping slipbowl 47 which may extend entirely around the circumference of the casinghanger 41 but is preferably in the form of a series of small slip bowlsas will be described hereinbelow with regard to FIGURES and 6.Positioned within each slip bowl 47 is a slip element or slip plate 50,preferably rectangular in shape, as shown in FIGURE 5, and held on theside of the casing hanger 41 in sliding engagement with the slip bowl 47by means of holding plates 51 and 52 (FIGURE 6) positioned on eitherside of the slip plate. The holding plates 51 and 52 overlap the edgesof the slip plate 50 as illustrated in FIGURES S and 6 to hold the slipplate against the casing hanger 51. The lower inner surface 53 of eachslip plate 50 is bevelled at the same angle as the slip bowl 47 so thatthe horizontal teeth or serrations 54 on the outer face of each slip 50contact the inner surface 55 of the casinghead 28 simultaneously andwith substantially equal force when forced thereagainst. As shown inFIGURE 6, the slips 50 are curved along at least their outwardlyextending face to conform with the curvature of the inner wall of theeasinghead 28.

Mounted above each slip plate 50 is one or more compression springs 56for normally urging the slip plate 50 downwardly when it is free tomove. For ease in cocking the slip plates 50 in a retracted position andcompressing the springs 56 thereabove, a removable retainer plate 57 issecured, as by screws 58 to the top of the casing hanger 41. Theretainer plate 57 extends downwardly on the outside of the casing hanger41 so as to cover, at least partially, the springs 56 in theircompressed position. Instead of employing a separate retainer plate 57over each set of springs above each slip plate 50, the retainer plate 57could be in the form of a circular cap adapted to fit down over all ofthe slip plates in the casing hanger and surround the entire top of thecasing hanger 41. The inner lower face 61 of the retainer plate 57 andthe outer upper face of the slip plate 50 are bevelled at the same anglewhich is equal to that of the slip bowl 47.

In order to lock each slip plate 50 in its inoperative position, forexample while shipping the casing hanger 41 to'the drilling location, atleast one screw 63 is provided which preferably extends through the slipplate 50 and is releasably connected to the body member of the casinghanger 41 in a screw-threaded engagement. Alternatively, in order tohold the slip plate in its raised position as illustrated in FIGURE 2,instead of the screw passing through the slip plate 50 it could bepositioned below the slip plate 50. At the same time the casing hanger41 is provided with latching elements which are remotely operable torelease the slips from their retracted position to their outwardlyextending position. These latching elements may take the form of a pin64 having a wedgeshaped or cone-shaped nose adapted to seat in acorrespondingly shaped recess 65 formed on the inner surface of the slipplate 50. Alternatively, the latching pin 64 may be positioned to engagethe bottom of the slip plate 50 when it is in its raised position. Thelatching pin 64 may be in two parts with a rear portion 66 being aseparate piece of metal which is merely in contact with the front halfof the pin 64 so as to give the entire pin 64- 66 a length suflicient sothat the pointed nose of the pin 64 extends into the recess 65 when therear end of the 4 portion 66 is flush with the inner wall of the casinghanger 41. Alternatively, as shown in FIGURE 7, the latching pin 64a maybe positioned opposite one of the grooves 67a formed on the innersurface of the casing hanger 41 for latching a connector tool thereto,as will be described hereinbelow.

In cocking the spring-loaded slip segments 50 of the present casinghanger 41 prior to running it in a well, the retainer plate 57 or platesare removed from the casing hanger 41 by removing the screws 58. Thelocking screws 63 are then inserted through the slips 50 and threadedinto the casing hanger of body member 41 in the position shown on theleft-hand side of FIGURE 2. The compression springs 56 are thenpositioned over the slip plate 50 and the retainer plate 57 is forceddown along with the springs and is again anchored by installing screws58 in the top of the body member 41. -In this position, as shown in theleft-hand side of FIGURE 2 of the drawing, the slips are in their cockedposition and would snap downwardly except for the locking screw 63.

At the drilling location the casing hanger 41 is screwthreaded or weldedat the top of a section of casing 40 in a conventional manner. Prior tolowering the top of the casing with its casing hanger 41 into the well,the short rear portions of the latching pin 66 are inserted throughholes from the inside of the casing hanger 41 and urged against thefront portion 64 of the latching pin to force it into the mating recesson the inner surface of the slip segment 50. The connector device 42 ofthe running tool is then inserted into the bore 46 of the easing hanger41 and securely latched to the casing hanger 41 by a series of outwardlyextendible latching dogs 70 adapted to seat in the grooves 67 on theinner surface of the casing hanger 41. The diameter of the connectorhousing 71 of the connector device 42 at the point opposite the latchingpin 6466 is substantially equal to the bore 46 of the casing hanger 41at that point so that the rear portion 66 of the latching pin cannotmove into the bore 46. In this condition the locking screw 63 may beremoved from each of the slip plates 50 with the latching pin 64 seatedin the recesses 65 now holding the slip plates 50 in their raisedinoperative position.

With the pipe string 23 connected to the top of the connector device 42,which in turn is latched to the inner surface of the casing hanger 41,the entire assembly is lowered from the barge 11 (FIGURE 1) downwardly,as illustrated, until the casing hanger 41 is seated on the shoulder 43(FIGURE 2) within the casinghead 28. At this time the connector device42 is unlatched from the casing hanger 41 and withdrawn upwardlytherefrom. As the connector housing 71 is withdrawn from the bore of thecasing hanger 41 the latching pins 64-66 are forced inwardly by thespring loaded slip plates attempting to move downwardly to a positionshown in the righthand side of FIGURE 2. At this time the connectorhousing 71 would be raised out of the casing hanger 41 sufficiently sothat the rear portion 66 of the latching pin is pushed into the bore 46of the casing hanger 41 where it drops to the bottom. If desired, thisportion 66 of the latching pin may be made of a friable plasticmaterial. In the event that the latching pin 64a is of the type shown inFIGURE 7, no additional portion 64 of the pin is needed and the rearportion of the latching pin 64a merely extends into the grooves 67awhere it is out of the way of anything moving down the bore of thecasing hanger 41.

Referring to FIGURE 2, the pipe string 23 and the conneetor device 42form a running tool for lowering the casing hanger 41 and the casing 40suspended therefrom into the well casinghead 28. The connector device 42comprises a connector housing 71 having a plurality ofoutwardly-'extendible latching elements 70 carried in vertical recessesin the side wall of the housing 71. The latching elements or dogs 70 areof a size so that they pass completely through the side wall of theconnector housing 71 and have a portion extending beyond the side wallof the housing 41, either into the grooves 67 in the inner wall of thecasing hanger 41 or into a piston chamber 72, preferably cylindrical inform, which is formed within the connector housing 71. Mounted forsliding vertical movement within the piston chamber 72 is an annularpiston 73 whose height is such as to permit a certain amount of verticalmovement within the piston chamber 72. A series of recesses or acircular recess or groove 74 is formed on the outer wall of the piston73 and is of a size to receive a portion of the latching dogs 70thereinto, as shown in the right-hand half of FIGURE 2. When thelatching dog 70 has entered the recess 74 and the piston 73 as far as itcan go, no portion of the latching dog 70 extends beyond the verticalside face of the connector housing 71. Each latching dog 70 is heldwithin the connector housing 71 by means of a holding pin 75 whichextends through a slot 76 in the latching dogs 70 that is wide enough topermit the horizontal movement of the latching dog relative to theconnector housing 71. The piston 73 is preferably provided with one ormore O-ring seals 77, 78 and 81.

Formed on the inner wall of the connector housing 71 is a seat orshoulder 82 adapted to receive thereon a dart 83 or any other suitabletype of closure member or plug for closing the bore 84 of the connectorhousing 71. In the event that cementing operations are to be carried outthrough the connector housing 71, a pipe string known as a cementingstring 85, may have its upper end connected to the lower end of theconnector housing 71.

The bottom of the piston chamber 72 is in communication with the bore 84of the connector housing 71 above the seat 82 by means of one or moreports 86. In one form of the running tool of the present invention, thespace in the piston chamber 72 above the piston 73, as shown on theleft-hand side of FIGURE 2, is in communication with the bore 84 of theconnector housing 71 at a point below the seat 82 through conduits 90,91 and 92 and port 93. Conduit 90 is arranged to be closed by means ofany suitable type of valve, such as a needle valve 94. Another conduit95 is provided which is normally closed by a check valve 96, the conduit95 being in communication between the top of the piston chamber 72 andthe outside of the tool.

In one mode of operation of the connector device 42, the latching dogs70 are forced into engagement with the grooves 67 of a casing hanger 41by applying a pressure fluid through check valve 96 and conduit 95 intothe top of the piston chamber 72 at a time when the needle valve 94 isset to close conduit 90. As the piston 73 is pushed downwardly by thefluid pressure, the latching dogs 70 are pushed horizontally outwardly,as shown in the left-hand half of FIGURE 2, while any fluid below thepiston 73 is discharged out the port 86. With the connector device 42engaging the easing hanger 41 it is possible to run the casing 40 andits hanger 41 into a casinghead 28 located on the ocean floor bylowering the connected devices by means of a pipe string 23. When thecasing hanger 41 has been seated in the casinghead 28, as illustrated inFIGURE 2, the latching dogs 71 are retracted from the engaging groove 67in the casing hanger 41 in the following manner. After the piston 73 hadbeen forced downwardly to cause the latching dogs 70 to engage thecasing hanger 41, the needle valve 94 is opened manually before theapparatus is run down through the water into position in the casinghead28. With the needle valve 94 open, a dart 83, or any other suitable typeof plug, is dropped or circulated down through the pipe string 23 andinto the bore 84 of the connector housing 71 where it seats on theshoulder 82. Seating of the dart 83 on the shoulder 82 isolates port 93from any pressure in the pipe string 23 above the dart 83. Hydraulicpressure fluid is then applied at the top of the pipe string 23(FIGURE 1) by means of a hose 24 which is connected to the top of thepipe string 23 after which hydraulic pressure fluid is pumped downthrough the pipe string 23 by pump 25. Since hydraulic pressure fluid isprevented by dart 83 (FIGURE 2) from continuing down the well, thehydraulic pressure fluid enters port 86 and flows beneath the piston 73to force the piston 73 upwardly to a position shown in the right-handhalf of FIGURE 2. When the piston 73 is in this position the latchingdogs 70 will be automatically forced into the wall of the connectorhousing 71 when tension is applied to the pipe string to pull the pipestring 23 and the connector device 42 out of the casing hanger 41. Thepipe string 23 and the connector device are then pulled upwardly to thebarge 11 at the surface.

In another form of the connector device 42, illustrated in FIGURE 2, theneedle valve assembly 94 is replaced by a ball-type spring-loaded checkvalve (FIGURE 3) which has a locking stem 101 that is adapted to bescrewed down and lock the ball 100 of the check valve on its seat at atime when a pressure fluid is being forced through the other check valve96 (FIGURE 2) to force the piston 73 downwardly and latch the dogs 70 inthe groove 67. After the dogs 70 are in their latched position, andprior to running the connector tool down into the water from the barge11 (FIGURE 1), the locking stern 101 (FIGURE 3) is unscrewed and backedoff so that the ball 100 of the check valve is again spring-loaded andopens for fluid to pass outwardly from piston chamber 72 throughconduits 90, 91 and 92 in a manner described with regard to FIGURE 2. Ingeneral, it is preferred that fluid from the top of the piston chamber72 be discharged at a point below the seated dart 83, at which point alower pressure exists than above the dart when a hydraulic fluid isbeing applied to the underside of the piston 73 to raise it and unlatchthe dogs 70. However, at times and in certain operations it may be foundsufiicient to discharge fluid from the top of the piston chamber 72directly into the space outside the connector housing 71. At thesetimes, the needle valve assembly 94 of the connector device 42 of FIGURE2 is replaced by a spring-loaded check valve 102 (FIGURE 4) whosecompression spring 103 holds the check valve 96 in place so as toprevent fluid from being discharged out conduit 90 and connectingconduit 104 (FIGURE 4) when a hydraulic pressure fluid is being appliedthrough check valve 96 (FIGURE 2) to force the piston 73 downwardly.Thus, at the time a pressure is applied to the bottom of the piston 73(FIGURE 4) fluid in the piston chamber 72 above the piston 73' is forcedoutwardly through conduits 90 and 104, past check valve 102, to bedischarged in the space outside the connector housing 71. The spring 103must be still enough to keep ball 96 on its seat and thereby keep theconduit closed when piston 73 is being moved against frictional forces.It must also be stiff enough to overcome cementing pressures.

The running tool of the present invention provides connector means whichare adapted to mate with a casing hanger for lowering a casing and itcasing hanger into seating position within a casinghead, with the entireapparatus being inserted through a blowout preventer if necessary.Afterwards, the connector means is adapted to be released hydraulicallyfrom a remote location such as a barge on the ocean surface.

The connector device 42 of FIGURE 2 may also be used to retrieve acasing hanger 41 and its casing 40 from a well in the event that thecasing 40 has not been cemented in the Well. This operation is carriedout by employing the connector device 42 of FIGURE 2 With the needlevalve 94 in an open position. The connector device 42 is lowered bymeans of pipe string 23 down through the water from a barge 11(FIGURE 1) and into the bore of the casing hanger 41. A cross-over dart105 (FIGURE 8) is then dropped or pumped down through the pipe string 23until it seats on seating shoulder 82. The dart 105 is provided with afishing neck 106 at the top thereof whereby the dart may be recoveredfrom the bore of the connector housing 71 in an emergency by a suitablefishing apparatus which may be lowered in a conventional manner, as on awire line. A conduit 107 extends downwardly through the cross-over dart.105 and out the side of the dart at a level opposite the port 93 in thelower end of the connector housing 71. The lower end of the dart isprovided with O-ring seals or other packing elements 108 and 109 mountedin spaced relationship on either side of the discharge end of conduit107 so as to seal the space between the outer surface of the dart 105and the inner surface or wall of the bore of the connector housing 71. Asecond conduit 110 is provided through the body of the dart 105 incommunication between the space below the dart and the space above theseat 82 substantially opposite the port 86 in the connector housing 71.A suitable annular packer member 111 is provided on the dart for closingthe space between the outer wall of the dart and the inner wall of thebore of the connector housing 71 so that the packer member 111 togetherwith the seat 82 close the space between the dart and the connectorhousing thus putting port 86 in communication through conduit 110 withthe space below the dart 105.

With the dart 105 in place, as shown in FIGURE 8, a pressure fluid isapplied through pipe string 23 (FIGURE 2) with the pressure fluidpassing downwardly through conduit 107 (FIGURE 8) of the dart 105 andthence through port 93, conduits 92 (FIGURE 2), 91 and 90 to the pistonchamber 72 above the piston 73. Pressure is thereby applied to thepiston 73 forcing it downwardly and causing the latching dogs 70 to beforced outwardly into the grooves of the casing hanger 41 or any othersuitable piece of equipment that is to be recovered from a well. As thepiston 73 moves downwardly within the piston chamber 72, fluid below thepiston 73 is forced out through port 86 and thence through conduit 110(FIGURE 8) of the cross-over dart 105 to be discharged down the well.Pressure fluid can then be cut off from the pipe string 23 and the pipestring 23 with its connector device 42 (FIGURE 1) and the equipmentsecured thereto pulled to the surface if hold-down slips are notemployed or if they have not functioned and set properly. While thepresent invention has been described with regard to lowering a wellcasing and casing hanger into a well, it is clear that the same runningtool and connector device may be employed to run other pieces ofequipment down to an underwater well or retrieve them from the well, asdesired.

I claim as my invention:

1. Casing hanger apparatus for hanging a string of casing in a well froma casinghead positioned at the head of the well and having a seatingshoulder therein, said casing hanger comprising a body member adapted tobe secured to the top of a well casing and having a bore therethrough, adownwardly and inwardly sloping seat formed on the outer surface of saidbody member for seating in said casinghead, slip bowl means on the outerface of said body member, vertically slidable hold-down slip meanscarried on said slip bowl means in a retracted position, said slip meansextending outwardly from the peripheral face of said body member in anoperative position to engage the inner wall of said casinghead whenseated and set therein, said slip means having contact faces of a formto prevent upward movement of said body member relative to saidcasinghead, spring means positioned in said body member above said slipmeans for urging said slip means downwardly at all times along said slipbowl means, and retractable latching means carried by said body memberand engaging said slip means, said retractable latching means having acamming surface on its outwardly extending end in engagement with saidslip means for a lateral distance no greater than the lateral extensionof said camming surface.

2. Casing hanger apparatus for hanging a string of casing in a Well froma casinghead positioned at the head of the well and having a seatingshoulder therein, said casing hanger comprising a body member adapted tobe secured to the top of a well casing and having a bore therethrough, adownwardly and inwardly sloping seat formed on the outer surface of saidbody member for seating in said casinghead, slip bowl means formed onthe outer face of said body member, vertically slidable hold-down slipmeans carried on said slip bowl means in a retracted position, said slipmeans extending outwardly from the peripheral face of said body memberin an operative position to engage the inner wall of said casingheadwhen seated and set therein, said slip means having contact faces of aform to prevent upward movement of said body member relative to saidcasinghead, spring means positioned in said body member above said slipmeans for urging said slip means downwardly along said slip bowl means,and retractable latching lements carried by said body member andengaging said slip means in sliding unlatching contact therewith, saidlatching elements being of a length so that they extend through the wallof said body member with the outer ends of said latching elementsextending in an operative position outwardly from the outer face of saidbody member when the inner ends of said elements are substantially flushwith the inner surface of said body member each of said latchingelements having a camming surface on its outwardly-extending end inengagement with said slip means for a lateral distance no greater thanthe lateral extension of said camming surface.

3. Casing hanger apparatus for hanging a string of casing in a well froma casinghead positioned at the head of the well and having a seatingshoulder therein, said casing hanger comprising a body member adapted tobe secured to the top of a well casing and having a bore therethrough, adownwardly and inwardly sloping seat formed on the outer surface of saidbody member for seating in said casinghead, slip bowl means recessedinto the outer face of said body member, vertically slidable hold-downslip means carried on said slip bowl means in a retracted position, saidslip means extending outwardly from the peripheral face of said bodymember in an operative position to engage the inner wall of saidcasinghead when seated and set therein, said slip means havinghorizontally-serrated faces, said serrations being sloped to preventupward movement of said body member relative to said casinghead, springmeans positioned in said body member above said slip means for urgingsaid slip means downwardly along said slip bowl means, removable lockmeans in contact with said slip means and releasably secured to saidbody member for locking said slip means in said retracted position onsaid slip bowl means against substantially vertical movement, andretractable latching elements carried by said body member and engagingsaid slip means in sliding unlatching contact therewith, said latchingelements being of a length so that they extend through the wall of saidbody member with the outer ends of said latching elements extending inan operative position outwardly from the outer face of said body memberwhen the inner ends of said elements are substantially flush with theinner surface of said body member.

4. Casing hanger apparatus for hanging a string of casing in a well froma casinghead positioned at the head of the well and having a seatingshoulder therein, said casing hanger comprising a body member adapted tobe secured to the top of a well casing and having a bore therethroughsubstantially equal to that of the casing, a downwardly and inwardlysloping seat formed on the outer surface of said body member for seatingin said casinghead, slip bowl means recessed into the outer surface ofsaid body member, vertically slidable hold-down means carried on saidslip bowl means in a retracted position, said slip means extendingoutwardly from the peripheral face of said body member in an operativeposition to engage the inner wall of said casinghead when seated and settherein, said slip means having horizontally-serrated faces, saidserrations being sloped to prevent upward movement of said body memberrelative to said casinghead, spring means positioned in said body memberabove said slip means for urging said slip means downwardly along saidslip bowl means, removable lock means in contact with said slip meansand releasably secured to said body member for locking said slip meansin said retractable position on said slip bowl means againstsubstantially vertical movement, retractable latching elements carriedby said body member and engaging said slip means in sliding unlatchingcontact therewith, said latching elements being of a length so that theyextend through the wall of said body member with the outer ends of saidlatching elements extending in an operative position outwardly from theouter face of said body member when the inner ends of said elements areflush 1% with the inner surface of said body member, said latchingelements being adapted to be held in an outwardly-extending operativeposition by a tool filling the bore of said body member at leastopposite said latching elements, and recess groove means formed in theinner wall of said body member for locking a tool therein.

References Cited in the file of this patent UNITED STATES PATENTS1,616,978 MacClatchie Feb. 8, 1927 1,794,662 Zerr Mar. 3, 1931 1,971,514Stone Aug. 28, 1934 2,094,812 Penick et al. Oct. 5, 1937 2,690,344 AllenSept. 28, 1954 2,824,757 Rhodes Feb. 25, 1958 2,843,349 Meyer July 15,1958 2,962,096 Knox Nov. 29, 1960

4. CASING HANGER APPARATUS FOR HANGING A STRING OF CASING IN WELL FROM ACASINGHEAD POSITIONED AT THE HEAD OF THE WELL AND HAVING A SEATINGSHOULDER THEREIN, SAID CASING HANGER COMPRISING A BODY MEMBER ADAPTED TOBE SECURED TO THE TOP OF A WELL CASING AND HAVING A BORE THERETHROUGHSUBSTANTIALLY EQUAL TO THAT OF THE CASING, A DOWNWARDLY AND INWARDLYSLOPING SEAT FORMED ON THE OUTER SURFACE OF SAID BODY MEMBER FOR SEATINGIN SAID CASINGHEAD, SLIP BOWL MEANS RECESSED INTO THE OUTER SURFACE OFSAID BODY MEMBER, VERTICALLY SLIDABLE HOLD-DOWN MEANS CARRIED ON SAIDSLIP BOWL MEANS IN A RETRACTED POSITION, SAID SLIP MEANS EXTENDINGOUTWARDLY FROM THE PERIPHERAL FACE OF SAID BODY MEMBER IN AN OPERATIVEPOSITION TO ENGAGE THE INNER WALL OF SAID CASINGHEAD WHEN SEATED AND SETTHEREIN, SAID SLIP MEANS HAVING HORIZONTALLY-SERRATED FACES, SAIDSERRATIONS BEING SLOPED TO PREVENT UPWARD MOVEMENT OF SAID BODY MEMBERRELATIVE TO SAID CASINGHEAD, SPRING MEANS POSITIONED IN SAID BODY MEMBERABOVE SAID SLIP MEANS FOR URGING SAID SLIP MEANS DOWNWARDLY ALONG SAIDSLIP BOWL MEANS, REMOVABLE LOCK MEANS IN CONTACT WITH SAID SLIP MEANSAND RELEASABLY SECURED TO SAID BODY MEMBER FOR LOCKING SAID SLIP MEANSIN SAID RETRACTABLE POSITION ON SAID SLIP BOWL MEANS AGAINSTSUBSTANTIALLY VERTICAL MOVEMENT, RETRACTABLE LATCHING ELEMENTS CARRIEDBY SAID BODY MEMBER AND ENGAGING SAID SLIP MEANS IN SLIDING UNLATCHINGCONTACT THEREWITH, SAID LATCHING ELEMENTS BEING OF A LENGTH SO THAT THEYEXTEND THROUGH THE WALL OF SAID BODY MEMBER WITH THE OUTER ENDS OF SAIDLATCHING ELEMENTS EXTENDING IN AN OPERATIVE POSITION OUTWARDLY FROM THEOUTER FACE OF SAID BODY MEMBER WHEN THE INNER ENDS OF SAID ELEMENTS AREFLUSH WITH THE INNER SURFACE OF SAID BODY MEMBER, SAID LATCHING ELEMENTSBEING ADAPTED TO BE HELD IN AN OUTWARDLY-EXTENDING OPERATIVE POSITION BYA TOOL FILLING THE BORE OF SAID BODY MEMBER AT LEAST OPPOSITE SAIDLATCHING ELEMENTS, AND RECESS GROOVE MEANS FORMED IN THE INNER WALL OFSAID BODY MEMBER FOR LOCKING A TOOL THEREIN.